Various model melanins, based upon precursors such as dopamine, cysteine, glutathione and mixtures thereof, have been characterized with W-band EPR spectroscopy. Spectra of different model melanins are markedly different. Particularly, the degree of solubilization of polymer correlates very well with the ratio of semiquinone and/or semiquinone imine signal to intrinsic free radical signal. Results indicate that model dopamine melanin is not a good model for neuromelanin, and that neuromelanin incorporates cysteine and/or glutathione. This is a continuing multi-year project.